Operation Manual

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ELM327
ELM327DSJ Elm Electronics – Circuits for the Hobbyist
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Programmable Parameter Summary (continued)
2C
2D
2E 80
(10000000)
2F 0A
(50 Kbps)
Protocol B (USER1) baud rate divisor. See PP 2B for a description.
00 to FF
E0
(11100000)
04
(125 Kbps)
01 to 40
00 to FF
Protocol C (USER2) CAN options. See PP 2C for a description.
Protocol C (USER2) baud rate divisor. See PP 2B for a description.
01 to 40
R
Protocol B (USER1) CAN options.
Each bit of this byte controls an option, as follows:
b7: Transmit ID Length 0: 29 bit ID 1: 11 bit ID
b6: Data Length 0: fixed 8 byte 1: variable DLC
b5: Receive ID Length 0: as set by b7 1: both 11 and 29 bit
b4: baud rate multiplier 0: x1 1: x 8/7 (see note 3)
b3: reserved for future - leave set at 0.
b2, b1, and b0 determine the data formatting options:
b2 b1 b0 Data Format
0 0 0 none
0 0 1 ISO 15765-4
0 1 0 SAE J1939
Other combinations are reserved for future updates – results will
be unpredictable if you should select one of them.
R
R
R
2B 02
(250 Kbps)
01 to 40Protocol A (SAE J1939) CAN baud rate divisor
baud rate (in kbps) = 500 ÷ (PP 2B value)
For example, setting this PP to 19 (ie. decimal 25) provides
a baud rate of 500/25 = 20 kbps.
R
2A 3C
(00111100)
00 to FF DCAN Error Checking (applies to protocols 6 to C)
Each bit of this byte controls an option, as follows:
b7: ISO15765 Data Length 0: accept any 1: must be 8 bytes
b6: ISO15765 PCI = 00 0: allowed 1: not allowed
b5: Search after ERR94 0: normal 1: CAN is blocked
b4: Search after LV RESET 0: normal 1: CAN is blocked
b3: Wiring Test 0: bypass 1: perform
Processing 7F xx 78’s:
b2: enabled (CAN & KWP) 0: no 1: yes
b1: valid Modes (xx values) 0: all 1: only 00 to 0F
b0: valid CAN protocols 0: all 1: only ISO15765
Notes: 1. The ELM327 does not accept decimal digits for the Programmable Parameters - all values are hexadecimal.
2. For Programmable Parameters that describe options in terms of bits, b7 is the msb, and b0 is the lsb.
3. When b4 of PP 2C or PP 2E are set, the CAN baud rate will be increased by a factor of 8/7, but the baud
rate displayed by the AT DP command will still show the base rate (as set by PP 2D or PP 2F). For example,
if you set PP 2C b4 to 1, and then PP 2D to 06, the base frequency will be 83.3 kbps. The AT DP command
will report 83 kbps, but the actual baud rate will be 83.3x8/7 = 95.2 kbps.
PP Description Values Default Type